A Synthesis of Decision Models for Tool Management in Automated Manufacturing

Abstract

The evidence is clear that a lack of attention to structured tool management has resulted in the poor performance of many manufacturing systems. Plant tooling systems affect product design options, machine loading, job batching, capacity scheduling, and real-time part routing decisions. With increasing automation in manufacturing systems, there is a growing need to integrate tool management more thoroughly into system design, planning and control. This paper critically evaluates various tool management approaches, identifying the operational tradeoffs and analyzing the models developed to address management decisions involving tooling. These decisions range from selecting the optimal machining parameters and the most economic processing rate for a particular operation, to the loading of tools and jobs on machines and the determination of the optimal tool-mix inventories needed for a particular production schedule. We present an integrated conceptual framework for resource planning to examine how tool management issues, depending upon their scope, can be classified into tool-level, machine-level, and system-level concerns. This framework specifies how decisions made at one level constrain those at lower levels, and how information from lower levels feeds back to higher level decisions. The framework structures our critical evaluation of the modeling approaches found in the academic literature and points to promising directions for future research.flexible manufacturing systems, production planning, CIM, performance evaluation, automated manufacturing systems

Scheduling with tool changes to minimize total completion time: Basic results and SPT performance

“…However, its origins being in the work on flexible machines, this literature has focused mainly on tool change induced by job mix rather than that due to tool wear; Akturk and Avci [2] is a notable exception. This is in sharp contrast to the finding in Gray et al [9] that in real life tool change due to tool wear is approximately 10 times more frequent than that induced by job mix. Furthermore, tool management research does not address the scheduling-related performance measures such as total completion time; the emphasis typically is on minimizing the number of tool changes.…”

“…This is perhaps due to the late recognition that lack of tooling considerations has led to the considerable under performance of automated manufacturing systems; see Gray et al [9]. However, its origins being in the work on flexible machines, this literature has focused mainly on tool change induced by job mix rather than that due to tool wear; Akturk and Avci [2] is a notable exception.…”

An exact tool allocation approach for CNC machines

“…Gray et al ( 1993) an d Vee ram ani et al ( 1992) give e xte nsive surve ys on the tool m anage m e nt issue s of autom ate d m an ufacturin g syste ms, an d e mph asize that the lack of toolin g con side ration s has re sulte d in th e poor pe rforman ce of the se syste ms. Kouve lis ( 1991) ide ntified cutting tool utilization as an importan t param ete r for the ove rall system perform ance . In this study, the cost of toolin g has bee n re porte d to be 25± 30% of the fixe d an d variable costs of production .…”

“…In this study, the cost of toolin g has bee n re porte d to be 25± 30% of the fixe d an d variable costs of production . Gray et al ( 1993) also pre se nt an in te grate d conceptual fram ework for re source plan ning to exam in e how tool m an age me nt issue s can be classifie d in to tool-le ve l, m ach in e-le ve l, an d syste m -le ve l concerns. Tool manage me nt de cision s arise in production plan nin g an d sche dulin g, and in volve m ach in e groupin g, part type se le ction and loadin g, and tool allocation at the syste m level.…”

“…Unfortu nate ly, these studie s also assume constant proce ssing tim es and tool live s, e ve n though the tool wear, conse quently the tool re placeme nt freque ncy, is dire ctly re late d with the m ach ining condition s sele ction . Furth e r, in the multiple operation case , non -m achin in g time com pon e nts, such as the tool re place me nts, can have a sign ifican t impac t on the total cost of production be cause of the re lative ly short tool live s of man y turn ing tools as stated by Gray et al ( 1993) . In the same study, the y re porte d that tools are chan ge d te n time s more ofte n due to tool wear than to part mix.…”